Add PSL linter written in Python

src/pslint.py

@@ -0,0 +1,185 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-#
+#
+# PSL linter written in python
+#
+# Copyright 2016 Tim Rühsen (tim dot ruehsen at gmx dot de). All rights reserved.
+#
+# Permission is hereby granted, free of charge, to any person obtaining a
+# copy of this software and associated documentation files (the "Software"),
+# to deal in the Software without restriction, including without limitation
+# the rights to use, copy, modify, merge, publish, distribute, sublicense,
+# and/or sell copies of the Software, and to permit persons to whom the
+# Software is furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+# DEALINGS IN THE SOFTWARE.
+
+import sys
+
+nline = 0
+line = ""
+warnings = 0
+errors = 0
+
+def warning(msg):
+  global warnings, line, nline
+  print('%d: warning: %s: \'%s\'' % (nline, msg, line))
+  warnings += 1
+
+def error(msg):
+  global errors, line, nline
+  print('%d: error: %s: \'%s\'' % (nline, msg, line))
+  errors += 1
+
+def lint_psl(infile):
+  """Parses PSL file and extract strings and return code"""
+  global line, nline
+
+  PSL_FLAG_EXCEPTION = (1<<0)
+  PSL_FLAG_WILDCARD = (1<<1)
+  PSL_FLAG_ICANN = (1<<2) # entry of ICANN section
+  PSL_FLAG_PRIVATE = (1<<3) # entry of PRIVATE section
+  PSL_FLAG_PLAIN = (1<<4) #just used for PSL syntax checking
+
+  psl = {}
+  section = 0
+
+  lines = [line.strip('\r\n') for line in infile]
+
+  for line in lines:
+    nline += 1
+
+	 # check for leadind/trailing whitespace
+    stripped = line.strip()
+    if stripped != line:
+      warning('Leading/Trailing whitespace')
+    line = stripped
+
+    # empty line
+    if not line:
+      continue
+
+    # check for section begin/end
+    if line[0:2] == "//":
+      if section == 0:
+        if line == "// ===BEGIN ICANN DOMAINS===":
+          section = PSL_FLAG_ICANN
+        elif line == "// ===BEGIN PRIVATE DOMAINS===":
+          section = PSL_FLAG_PRIVATE
+        elif line[3:8] == "===BEGIN":
+          error('Unexpected begin of unknown section')
+        elif line[3:6] == "===END":
+          error('End of section without previous begin')
+      elif section == PSL_FLAG_ICANN:
+        if line == "// ===END ICANN DOMAINS===":
+          section = 0
+        elif line[3:8] == "===BEGIN":
+          error('Unexpected begin of section: ')
+        elif line[3:6] == "===END":
+          error('Unexpected end of section')
+      elif section == PSL_FLAG_PRIVATE:
+        if line == "// ===END ICANN DOMAINS===":
+          section = 0
+        elif line[3:8] == "===BEGIN":
+          error('Unexpected begin of section')
+        elif line[3:6] == "===END":
+          error('Unexpected end of section')
+
+      continue # processing of comments ends here
+
+    # No rule must be outside of a section
+    if section == 0:
+      error('Rule outside of section')
+
+    # decode UTF-8 input into unicode, needed only for python 2.x
+    if sys.version_info[0] < 3:
+      line = line.decode('utf-8')
+
+	 # each rule must be lowercase (or more exactly: not uppercase and not titlecase)
+    if line != line.lower():
+      error('Rule must be lowercase')
+
+    # strip leading wildcards
+    flags = 0
+    # while line[0:2] == '*.':
+    if line[0:2] == '*.':
+      flags = PSL_FLAG_WILDCARD | PSL_FLAG_PLAIN | section
+      line = line[2:]
+
+    if line[0] == '!':
+      flags = PSL_FLAG_EXCEPTION | section
+      line = line[1:]
+
+    # wildcard and exception must not combine
+    if flags & PSL_FLAG_WILDCARD and flags & PSL_FLAG_EXCEPTION:
+      error('Combination of wildcard and exception')
+
+    labels = line.split('.')
+
+    for label in labels:
+      if not label:
+         error('Leading/trailing or multiple dot')
+         continue
+
+      if label[0:4] == 'xn--':
+         error('Punycode found')
+         continue
+
+      if '--' in label:
+         error('Double minus found')
+         continue
+
+      # allowed are a-z,0-9,- and unicode >= 128 (maybe that can be finetuned a bit !?)
+      for c in label:
+        if not c.isalnum() and c != '-' and ord(c) < 128:
+          error('Illegal character')
+          break
+
+    if line in psl:
+      """Found existing entry:
+         Combination of exception and plain rule is ambiguous
+           !foo.bar
+            foo.bar
+
+         Allowed:
+           !foo.bar + *.foo.bar
+            foo.bar + *.foo.bar
+      """
+      error('Found doublette/ambiguity (previous line was %d)' % psl[line])
+      continue
+
+    psl[line] = nline
+
+
+def usage():
+  """Prints the usage"""
+  print('usage: %s PSLfile' % sys.argv[0])
+  print('or     %s -        # To read PSL from STDIN' % sys.argv[0])
+  exit(1)
+
+
+def main():
+  """Check syntax of a PSL file"""
+  if len(sys.argv) < 2:
+    usage()
+
+  if sys.argv[-1] == '-':
+    lint_psl(sys.stdin)
+  else:
+    with open(sys.argv[-1], 'r') as infile:
+      lint_psl(infile)
+
+  return errors != 0
+
+
+if __name__ == '__main__':
+  sys.exit(main())